Harrow · Greater London
Misted Glass Repair in Harrow
Cloudy, streaky double glazing in Harrow is usually a failed sealed unit, and we can quote to replace it without disturbing the frame.
- HA1
- HA2
- HA3
- HA5
- HA7
- Guide from £155
Foggy window replacement in Harrow
Some services offer to drill the glass, flush the cavity and add a vent instead of replacing the unit. This can improve the look, but it does not restore the original seal, and any gas fill that helped the unit insulate has already been lost. Replacement restores a sealed cavity.
If the misted unit is in a door, beside a door or low down near the floor, the replacement should be safety glass. In England, Approved Document K sets out these critical locations, and the replacement unit should meet them even if the original glass did not.
Condensation on the room-side surface of the glass is not the same problem. It usually comes from humid indoor air meeting a cold pane and can be wiped away. Only mist trapped between the two panes means the sealed unit itself has failed and needs replacing.
A new unit has to match the overall thickness of the old one so it sits in the existing rebate and takes the original beads. The glazier also notes any Georgian bars, leaded designs or obscure patterns so the replacement matches the other windows in the room.
Included as standard
- Survey to confirm the mist is inside the unit
- Removal of old units and cleaning of rebates
- Measurement of each failed sealed unit
- Written quote fixing the price for the specification
About Harrow for this job
- Postcodes covered
- HA1, HA2, HA3, HA5, HA7 and the surrounding area, including Wembley, Northolt and Greenford
- Coast
- Harrow is well inland, around 50 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Harrow the midwinter sun reaches about 15° above the horizon at noon, with roughly 7.6 hours of daylight, rising to about 62° and 16.4 hours in midsummer. Units on sunny south and west elevations go through bigger daily temperature swings, which stresses the edge seal over time. In colder, darker months, mist between the panes is often most visible, so the survey is a good time to confirm failure.
- Access and setting
- In flats and terraced streets, replacing misted units often means planning access, parking and carrying units up stairs. Upper-floor windows may need to be done from inside, and conservation areas may require matching bars or glass patterns.
- Rules in England
- Approved Document K requires safety glass in critical locations in England: glazing in doors and in side panels within 300 mm of a door, up to 1500 mm above floor level, and any glazing in walls or partitions up to 800 mm above floor level.
Guide prices in Harrow
| Typical job | Guide price inc VAT |
|---|---|
| One misted unit, 600 × 900 mm | £155 – £195 |
| Two misted units, 600 × 900 mm | £305 – £395 |
| Four misted units, 600 × 1100 mm | £685 – £875 |
| Misted unit in a door, toughened | £305 – £385 |
Get a guide price for your size
Approved Document L sets the minimum energy performance for replacement windows and doors in existing homes in England: a U-value of 1.4 W/m²K, or Window Energy Rating band B for windows; doors can instead meet a Door Set Energy Rating (band B, or band C for doors more than 60% glazed); rooflights need 2.2 W/m²K.
Choosing your misted glass repair
Georgian bar or leaded
Decorative bars or lead designs remade to match the originals so the new unit lines up with neighbouring windows.
Obscure glass unit
Patterned glass for bathrooms, landings and front doors, chosen to match existing obscure panes or to add privacy.
Toughened safety unit
Both panes toughened, for misted units in doors, beside doors or low down where safety glass is required.
Misted Glass Repair in Harrow: questions
How much does it cost to replace a misted sealed unit?
The cost depends on the size of the unit, the glass type, any Georgian bars, leaded or obscure features, how many units are done together, and access to the window. Larger units, safety glass and upper-floor windows cost more. See the guide prices for typical sizes, then get a written quote for your exact windows.
Does misted double glazing lose heat?
A misted unit usually insulates less well than when it was new, because any insulating gas in the cavity has escaped and been replaced with damp air. The mist itself also reduces clarity. Replacing the unit restores a sealed cavity, and choosing a low-E unit can improve on the original performance where the old unit was plain glass.
Can you clean the inside of a misted double glazing unit?
Not without breaking the seal. Some firms drill the glass, flush the cavity and fit a small vent, which can clear the mist for a while. It does not restore an airtight seal or gas fill, and white staining may not fully clear. Replacing the unit is the reliable way to restore a clear, sealed cavity.
Is it worth replacing misted units or should I get new windows?
If the frames are sound, square and the hinges and locks work, replacing only the misted units is usually the more economical option. New windows make more sense if the frames are rotten, warped, draughty or hard to open. The glazier checks the frames at the survey and the quote will say if replacing units is not good value.
Do you cover Harrow for misted glass repair?
Yes. We can quote for misted glass repair across Harrow and the surrounding Greater London area, including postcode districts HA1, HA2, HA3, HA5 and HA7, and nearby Wembley, Northolt and Greenford. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
More glazing in Harrow
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